Taken as an aggregate, rare cancers (those affecting fewer than 200,000 people in the US according to the Orphan Disease Act definition) account for 27% of the US cancer diagnoses and 25% of cancer mortality. However, while new therapies have changed the way some common cancers are treated, there has been little advance in the treatment of most rare cancers and research directed at these diseases is sparse. The main goal of this application is to launch a research program aimed at deepening the understanding of the etiology and long-term outcomes of patients diagnosed with rare cancers. For our analyses, we will utilize data collected by the Cancer Genetics Network (CGN) and the Rare Cancer Genetics Registry (RCGR). The CGN, developed in 1998, has over 15,000 participants with cancer (of whom 873 had a rare cancer) in addition to over 5,000 of their unaffected family members. The RCGR, funded by an NIH Challenge grant in 2009, has over 400 participants with rare cancers recruited by a subset of the CGN sites. Dr. Finkelstein is the PI of the both the CGN and the RCGR. Neither the CGN nor the RCGR provided funding to support analysis of the data collected for the registries. This application plans to undertake analyses of the characteristics associated with elevated risk of rare cancers, as well as long-term outcomes of these diseases. Specific Aims include: 1. Create a single research data set from data collected in the CGN and RCGR consisting of subjects with rare cancers, those with more common cancers, and unaffected family members of participants. Available data include demographics, lifestyle and environmental exposures, medical and family history, genetic test results, cancer diagnoses, co-morbidities, treatment and survival status. On CGN participants, we have over 10 years follow-up of clinical, psychological and physical outcomes of disease and treatment. 2. Using the combined CGN and RCGR data, determine the clinical, demographic, environmental, life-style, and family history characteristics associated with an elevated risk of each rare cancer type. Questions of interest include whether rare cancer patients have a higher rate of exposures such as smoking or a different profile of family cancer history than people who do not get these cancers. 3. Using long-term (10 year) follow-up data from CGN registrants, determine the long-term outcomes in rare cancer survivors. Questions of interest include what are the risks of co-morbidities (such as heart disease) and second primary cancers, and how do these risks compare between patients with the rare cancer versus unaffected controls? What are the risks of psychological symptoms (memory loss, fatigue, depression) and are these more common than unaffected (controls)? Than in patients with common cancers? What are the demographic, clinical, lifestyle and treatment predictors of physical and psychological long-term complications in patients with rare cancers? Analyses will be done separately within each rare cancer site when possible. and an aggregated analysis using all data, accounting for age, diagnosis, registry and site will be done.